Acetyl cellulose.



. UN TED STATES iBatented July 21, 1903.

OFFIC PATENT ARTHURQEIOHENGRUN AND THEODOR BECKER, on ELBERFELD, GER- MANY, ASSIGNORS T0 FARBENFABRIKEN OFELBERFELD 00., or 1 NEW YORK, N. Y., A CORPORATION on NEW YORK.

I'ACETYL CELLULOSIE.

SPECIFICATION forming part of Letters Patent No. 734,123, dated July 21, 1903.

- Application filed January 8, 1902. Serial No. 88,899. (Specimens) To all whom, it mag concern."

Be it known that we, ARTHUREICHENGRIJ'N and THEODOR BECKER, doctors of philosophy, chemists, residing at Elberfeld, Germany, (assignors to the FARBENFABRIKENOF ELBERFELD Co. of-New York,) have invented a new and useful Improvement in Acetylized Derivatives of Cellulose; and we hereby declare the following to be a clear and exact description of our invention.

Our invention relates to the production of a new 'acetylized derivative of cellulose,

which is characterized by the fact that it is readily soluble in alcohol. The process for preparing this new body consists in treating hydroc'ellulose with a mixture of acetic anhydrid and sulfuric acid.

Our process dilfers from that described in Letters Patent No. 654,988 by Lederer in that we employa'larger qnantityof sulfuric acid. In contradistinction to the acetyl cellulose obtained by Lederer our new acetylizd derivative .of cellulose is soluble inalcohol.

, In carrying out the new process practically we can proceed as follows, the parts being'by weight: One hundred and twenty-five partsof hydrocellnlose are introduced into a mixture prepared from five hundredparts of glacial acetic acid, five hundred parts of acetic anhydrid, and twenty five parts of sulfuric acid of 66 Baum. The reaction mixture is allowed to stand at the ordinary temperature on stirring it from time to time. After some hours the hydrocellulose is dissolved, and the reaction mass forms a thin liquid solution which can easily be filtered. Subsequently UGSSQS.

. it is poured into water, by which meansthe new product is precipitated in the shape of white flakes, which are filtered off and dissolved in five times its quantity of alcohol. 011 cooling the resulting solution grows stiff to a mass like gelatin.

The new acetylized derivative ofcellulose is a white mass readily soluble in alcohol. Its concentrated alcoholic solution represents in the cold a solid mass like gelatin, which, liquefies on heating or on adding alcohol.

From the solutions in alcohol, acetone, glacial acetic acid, or the like the new body is precipitated in the shape of white flakes by the addition of water.

Having now described ourinvention and in what manner the same is to be performed, whatwe claim as new, and desireto secure by Letters Patent, is-

The herein-described acetyl cellulose characterized by being readily soluble in alcohol,

its concentrated alcoholic solution representing in the cold a solid mass like gelatin which turns liquid again on heating, being precipitated in the shape of white flakes-from its solutions in al'cohol,'acetone or glacial acetic acid by the addition of water, substantially as hereinbefore described.

In testimony whereof we have signed our names in the presence of two subscribing wit- ARTHUR EICI-IENGRUN. TllEODOR BECKER. Witnesses:

OTTO KONIC, J. A. RITTERSIIAUS. 

